1. Field of the Invention
The present invention relates to a method and apparatus for cleaning endoscope lenses including a disposable endoscope sheath providing effective flushing of surgical debris from the distal viewing end of an endoscope, in the body.
2. Discussion of the Prior Art
Endoscopes permit remote viewing of a surgical site while a surgical procedure is being performed. During surgery, blood, tissue or other debris from the surgical site can splatter onto the viewing end of the endoscope, thereby impairing the field of view through the endoscope. The surgical debris obscuring the field view of the endoscope must be removed and so, using methods of the prior art, it is necessary to interrupt the procedure and remove the endoscope for cleaning, thereby unnecessarily prolonging the procedure.
Because of the inconvenience of removing and cleaning an endoscope during surgery, some surgeons prefer to use an endoscope with a sheath having a provision for flushing away surgical debris obscuring the endoscope view. Endoscope sheaths of the prior art are generally custom fitted to the endoscope and often include air tubes, water tubes or suction tubes to flush away or suction away surgical debris from the viewing end. The irrigation, suction and air tubes on the endoscope sheath often add significant girth to the profile of the endoscope, thus requiring a relatively large incision to accommodate the sheath and endoscope together. Since endoscopes are of different lengths, a variety of corresponding sheath lengths are required to provide a compatible sheath for each endoscope length.
Another problem associated with endoscope lens cleaning systems of the prior art is that often, after flushing or irrigating the distal end of the endoscope, a droplet of irrigating fluid remains on the endoscope lens, thereby providing a substantial distortion and obscuring the surgeon""s field of view.
In order to overcome the problem of leftover droplets on the endoscope lens, the Xomed(copyright) Endoscrub(copyright) sheath was developed for use with the Endoscrub(trademark) lens cleaning system, whereby a pump dispensing saline irrigation fluid is operated first in the forward direction, to provide an outward flow of irrigating fluid, followed by a short suction pulse, to retract or withdraw saline droplets clinging to the distal end of the endoscope and back into the sheath lumen or irrigation space. One problem which has been observed when using the Endoscrub(copyright) lens cleaning system, however, is that often blood or other surgical debris can also be drawn back into the sheath lumen or irrigation space where the accumulated debris may hinder later operation of the Endoscrub(copyright) lens cleaning system.
It has also been observed that a clinician may be required to change endoscopes and sheaths during a procedure, and if the irrigation fluid tubing set is attached to the sheath by conventional friction fit, it is difficult to change sheaths, and thus endoscopes, during the procedure. The tubing set is connected to the irrigation fluid pump and so it is awkward for the clinician to have to change the tubing set each time it is desired to change the endoscope to a differently dimensioned endoscope.
Another problem encountered in using the Xomed(copyright) Endoscrub(copyright) system is that use of a foot pedal to initiate the scrub cycle contributes to a proliferation of foot pedals on the operating room (OR) floor. Since many other powered instruments and sensor systems utilize foot pedals, adding a foot pedal for the endoscope system to the existing clutter on the OR floor makes it that much more difficult to control the lens cleaning system.
Another problem associated with endoscope cleaning systems utilizing peristaltic pumps is that tubing elasticity limits the precise control of the fluid dispensed at the tip of the sheath. If the tubing is made from a more pliable durometer material, the tubing set is more amenable to use in a peristaltic pump, however, the more pliable durometer tubing also blows up or expands in response to pressurization during pumping and is provides less control over the exact volume of fluid dispensed at the endoscope tip. Ideally, tubing supplying saline to the endoscope distal end through the peristaltic pump would not comprise the ability of the pump controller to control the volume and timing of fluid dispensed at the endoscope tip.
There is a need for a method and apparatus for cleaning the distal end of an endoscope which overcomes the problems associated with the prior art.
Accordingly, it is a primary object of the present invention to overcome the problems associated with the prior art by providing an endoscope lens cleaning system having an endoscope sheath, tubing set and software controlled pump providing a pre-programmed sequence of scrub cycles consisting of a flush intervals with forward actuation of the pump to dispense irrigation fluid over the endoscope lens for a selected duration, a brief pause interval to allow any residual pressure to dissipate, and a suction pulse interval with reverse actuation of the pump to retract any droplets of fluid remaining on the lens into the sheath lumen or irrigation space.
A further object of the present invention is to eliminate the problem of accumulated surgical debris within the sheath lumen or irrigation space, restoring optimal cleaning performance, by executing a purge cycle every third scrub cycle, where the purge cycle includes an extra long flush interval, flushing any residual body fluids, debris or air from the sheath lumen.
An additional object of the present invention is to provide an easily connected fluid path including a fluid tight, readily disconnectable luer connector, thereby permitting the irrigation tubing to be attached and detached to the sheath quickly and easily when changing endoscopes.
Another object of the present invention is providing an ideally positioned, sheath-mounted finger activated switch, thereby obviating the requirement for an additional foot pedal cluttering the OR floor.
Yet another object of the present invention is more precisely controlling the volume of irrigation fluid dispensed at the tip of the sheath with a specially adapted irrigation tubing set having lesser cross sectional elasticity.
The aforesaid objects are achieved individually and in combination, and it is not intended that the present invention be construed as requiring two or more of the objects to be combined unless expressly required by the claims attached hereto.
In accordance with the present invention, an endoscope lens cleaning system for use in removing surgical debris from the objective lens of an endoscope has a sheath adapted to receive the endoscope, carrying a control switch and having an open distal end in fluid communication with a proximally mounted luer lock for removably engaging the distal luer connection of a tubing set. The tubing set is connected to and engaged with a peristaltic pump including a microprocessor or controller adapted to respond to actuation of the control switch and execute software including program steps for operation of the pump.
In the preferred embodiment, the pump controller is programmed to execute a scrub cycle each time the clinician actuates the control switch mounted on the preferably disposable sheath. Scrub cycles are executed in a sequence of steps including a flush interval with a forward or outflow motion of the pump to dispense a first selected volume of irrigation fluid through the sheath and over the endoscope objective lens; a brief pause interval follows, to allow any residual fluid pressure to dissipate, and a suction pulse interval with a reverse or inflow motion of the pump next withdraws or retracts any residual fluid droplets from the endoscope objective lens and into the sheath lumen or irrigation space. The pump controller is programmed to perform two normal scrub cycles followed by a longer scrub cycle called a clear or purge cycle. The purge cycle differs from the ordinary or normal scrub cycle in that the flush interval dispensing irrigation fluid over the endoscope objective lens is of longer duration than in normal scrub cycles, approximately 2 seconds, thereby flushing any residual body fluids, other surgical debris or air from the sheath and restoring optimal lens cleaning system performance.
The pump is controllable in one of preferably six user selectable modes to determine flush interval forward run times according to a preprogrammed table. The pump preferably includes a separate control for enabling or disabling the clear or purge cycle. Additionally, the pump controller is programmed to respond to a continuous purge command; when the control switch is depressed and in the closed position longer than the programmed flush interval, the pump continues to run in the forward mode until the control switch is released.
Preferably, the pump controller is responsive to an eight-position rotary selection switch and provides an indicator signal to a light emitting diode (LED) or other visually perceptible indicator. The eight-position rotary selection switch provides selection of the mode of operation for the pump, corresponding to pre-programmed operating steps in the pump controller, the pump modes are: OFF, PRIME, MODE ONE, MODE TWO, MODE THREE, MODE FOUR, MODE FIVE and MODE SIX. The pump controller is programmed to illuminate the LED at any setting other than xe2x80x9c0xe2x80x9d or xe2x80x9cOFFxe2x80x9d under normal conditions. The controller running the software within the pump receives and decodes the input of the eight position rotary switch, placing the pump in a mode associated with the selected rotary switch position. As noted above, each pump mode has a unique scrub cycle including a selected flush interval duration and suction pulse duration. The pump controller detects the operation of the momentary contact control switch preferably mounted on the endoscope sheath and executes a flush interval upon sensing that the momentary contact control switch has been depressed, continuing to pump in the flushing or forward direction for as long as the control switch is depressed. When the control switch is released, the scrub cycle is completed by stopping, pausing and then operating in the reverse direction, as noted above.
Additionally, the controller controls the LED indicator, illuminating the LED to indicate pump status by remaining on when the pump is on or by flashing or blinking when an error has occurred. Finally, the controller software senses the power bus status, allowing for constant operation over a wide voltage range. The pump motor functions at only one speed regardless of the power bus voltage, thus allowing the device to operate consistently over a variety of input power conditions. If the power bus is not within acceptable limits, the LED is programmed to flash, indicating an error.
In the preferred embodiment, the irrigation tubing attaches to the sheath via a quick connect mechanism (e.g., a luer lock connector). The luer connector enables the clinician to freely change sheaths and endoscopes during a procedure, without the need to change the tubing set engaged with the pump.
The finger activated control switch is preferably releasably mounted directly on a disposable sheath, as opposed to being incorporated in a foot pedal. The sheath-mounted finger-activated switch is a normally-open spring biased momentary-contact switch electrically connected to the pump controller and is reusable and readily sterilized by autoclave or cold soaked sterilization methods.
Advantageously, the irrigation tubing set for use in the method and apparatus of the present invention has a first tubing section of pliable 50 durometer tubing in the upper portion to allow proper peristaltic pump operation and is connected in series with a second section made of more rigid 70 durometer tubing to eliminate uneccessary cross sectional elasticity. The two tubing sections are connected with a barbed conduit adapter. The distal end of the tubing set includes a luer lock adapted to receive the luer connector on the endoscope sheath. The proximal end of the tubing set includes a spike connector sheathed in a spike cover. The tubing set, as provided to the user, includes a slide clamp adapted to occlude or shut off flow of fluid flowing through the tubing.
The foregoing and additional objects, features and advantages of the invention will become apparent to those of skill in the art from the following detailed description of a preferred embodiment, taken with the accompanying drawings wherein like reference numerals in the various drawings identify like components.